Insulating and reinforcing means for junctures between insulated conductors and external appliance leads



Dec. 19, 1967 D. OAKMAN 3,359,353

INSULATING AND REINFORCING MEANS FOR JUNCTURES BETWEEN INSULATED CONDUCTORS AND EXTERNAL APPLIANCE LEADS Filed Jan. 20, 1967 1N VEN TOR. lou/sfl. Q4/0 14 Z W-Mz United States Patent 3,359,363 INSULATING AND REINFORCING MEANS FOR JUNCTURES BETWEEN INSULATED CONDUC- TORS AND EXTERNAL APPLIANCE LEADS Louis D. Oakman, Westlake, Ohio, assignor to Hysol Corporation, Olean, N.Y., a corporation of New York Filed Jan. 20, 1967, Ser. No. 610,682 2 Claims. (Cl. 174138) ABSTRACT OF THE DISCLOSURE A device for field use in joining insulated conductors to external appliance leads comprising an essentially cylindrical flexible plastic pod having one end apertured to closely envelop an appliance, the other end having one or more tapered extensions adapted to be cut for snug engagement with insulated conductors of diiferent diameter, an aperture in a flattened offset in the cylindrical wall, and detachable closure means for said aperture, whereby mounting said device on insulated conductor(s) while joining each bared conductor end with an appliance lead, then sliding the device into registering engagement with the appliance, filling the device with thermosetting plastic insulating material and inserting the aperture closure provides quick, reliable insulation and substantial mechanical reinforcement of the conductorappliance junction.

Background of the invention It is becoming standard practice in the production of various appliances or components of electrical circuits to provide such appliances with short protruding metallic leads to which bared ends of insulated conductors can be joined by soldering, mechanical crimping and the like. The normal practice has been to bind such junctions with insulating tape, but this practice leaves much to be desired since windings of tape which may seem secure are frequently not moisture proof. Furthermore, such tape windings add little to the mechanical strength of the conductor-lead juncture; and the appearance of bulky tape windings can be deceptive concerning both the mechanical and the electrical safety of the assemblage.

The invention The new device according to the present invention, when used in the intended manner, can be applied more quickly than the conventional insulating tapes, and by providing for the encasement with thermosetting plastic of not only the juncture per se, but a portion of the appliance and a substantial length of insulated conductor, assures eflfective insulation, complete protection from moisture, and mechanical reinforcement and strengthening of the assemblage. These advantages are accomplished by employing an essentially cylindrical flexible pod or casing, suitably fashioned from polyethylene, polypropylene or other flexible plastic material, having one or more tapered extensions at one end thereof adapted to be cut off to closely engage the outer surfaces of insulated conductor(s), an enlarged opening at the other end to provide close, resilient peripheral engagement with a cylindrical portion of an appliance, and an orifice or opening in the cylindrical wall intermediate said ends through which to introduce a thermosetting resin composition.

Thermosetting resin compositions which will cure and harden at room temperature within a short time interval min. to 2-3 hours), and which have desirable electric insulating properties and flexibility when cured are well known in the art. For example, various epoxy resin systems in which resin and hardener components are supplied separately, and mixed just prior to use, will provide the desired combination of rapid cure and mechanical and electrical properties. Suitably the resin composition may be supplied in a flexible tube which provides an amount of composition appropriate to fill one pod or casing as mounted on a conductor-appliance juncture with such tube having a rupturable diaphragm or other means for mixing the resin components just prior to use.

Even a resin composition having a 15 minute gelling or setting time would be impractical for field use if the assemblage was required to be kept stationary and upright during this period. An important part of the new insulating means, therefore, is to provide the sealing off of the side orifice as soon as the pod cavity has been filled with resin. This could be accomplished by applying plastic tape over the orifice. It is preferable, however, to provide a plug which will snap into the orifice and have a locking engagement with the periphery thereof.

When the orifice has been thus sealed the assemblage can be freely moved, or left unattended, with assurance that the resin composition will set to complete a proper insulating bond between the insulated conductor(s) and the appliance. Sealing of the orifice has the further advantage of eliminating curing time as a critical factor in selecting the resin composition, thereby providing much wider choice in selecting resin compositions having the desired combination of electrical and mechanical properties when cured.

The invention will be more readily understood from a consideration of the following description taken together with the accompanying drawing in which a preferred adaptation of the invention has been illustrated with the various parts thereof identified by suitable reference characters in each of the views and in which:

FIG. 1 is a plan view of a pod or casing in accordance with the invention, with part of the structure broken away and in section.

FIG. 2 is a sectional view substantially on the line 22 of FIG. 1.

FIG. 3 is a partial sectional view of a pod extension as shown in FIG. 1, indicating the cutting thereof to properly fit an insulated conductor.

FIG. 4 is a view showing orientation of the pod on a conductor while joining the conductor to an appliance lead.

FIG. 5 is a view similar to FIG. 4, but showing the pod moved into enveloping engagement with the appliance.

FIG. 6 is a sectional view substantially on the line 66 of FIG. 5, indicating the filling of the pod with liquid resin; and

FIG. 7 is a sectional view similar to FIG. 6 showing the pod substantially filled with solidified resin.

As shown in the drawing, the pod or casing 10 comprises an essentially cylindrical body part 11, having one or more tapered extensions 12 protruding from one end thereof, and a gradually in-turned shoulder 13 at the other end thereof, forming an enlarged end aperture 14 for circumferentially engaging a portion of an appliance. The pod 10 is suitably molded from flexible plastic, such as polyethylene, polypropylene, or the like, and is of relatively thin-walled structure, as indicated in the sectional showings.

The periphery of the aperture 14 has a smoothly rounded surface 15 forming a continuation of the inner surface of the pod, and this rounded contour, coupled with the flexibility of the wall structure, permits the aperture 14 to closely and sealably engage cylindrical portions of appliances having somewhat different diameters.

The tapered extensions 12 are of essentiall uniform wall thickness throughout. the major portion of their length, and have a length preferably about four times the diameter at the widest portion of the taper to facilitate accommodation of different sized insulated conductors as hereinafter described.

Centrally of the body part 11, the wall structure is offset to provide a flattened area 16, having an aperture 17 therein providing access to the interior of the pod or casing for filling with resin as hereinafter described.

While the pod 10 has been shown with two tapered extensions 12 adapted to receive two insulated conductors, it will 'be understood that in adapting the device to use with different appliances, the number of such tapered extensions required will depend on the number of appliance leads, and it is within the scope of the invention to employ one, two, three, or more extensions 12 on the pod 10 in adapting the same to different uses. Similarly, in adapting the device to different uses, the diameter of the body part 10, andthe diameter of the end aperture 14 therein, will be suitably varied to accommodate different type appliances. Typical appliances for which the device is particularly suited include fuse holders, connectors, lamp sockets, and the like.

In use of the device, an insulated conductor 18 with which it is to be associated is inserted through the device to engage the inner surface of a tapered extension 12, as indicated in FIG. 3. A small diameter conductor 18 will extend further into the tapered extension 12 than a larger diameter conductor 18 but the extent of penetration will be readily detected from the outside of the extension 12 due to slight outward distortion of the flexible walls thereof or, in the case of translucent or transparent plastic walls, by visualized appearance of the conductor within the extension 12. The end of the extension 12 which protrudes beyond the conductor 18, 18' is removed by means of a knife or other cutting implement 19, as diagrammatically indicated in FIG. 3 of the drawing.

The conductor 18 is then withdrawn from the extension 12 and inserted in the reverse direction through the severed end 12a and passed through the device to protrude beyond the apertured end 14, as seen in FIG. 4. A portion of the insulation is then removed from the conductor to expose the bare conductor 18a, which is crimped, soldered or otherwise secured to an electrical lead 20 of an appliance 21.

Having thus completed the electrical juncture, or the several junctures if the appliance has more than one lead to which conductors are being applied, the pod or casing 10 is slid along the assemblage to bring the apertured end 14 into firm peripheral engagement with the appliance 21, as indicated in FIG. 5. Liquid resin composi tion 22 is then introduced to the interior of the pod or casing 10 through a suitable nozzle or feed tip 23 of a size to freely enter the aperture 17, as indicated in FIG. 6. When the pod or casing 10 has been substantially filled, with resin, the tip 23 is withdrawn, and the aperture 17 is then sealed by means of tape, or preferably by means of a plug 24 having snap engagement with the aperture 17 as shown in FIG. 7. The assemblage can then be left unattended or moved about, if necessary, with assurance that within a short time interval characteristic of the particular thermosetting resin composition employed, the resin will gel or harden to the solidified state indicated at 22a in FIG. 7, to provide complete envelopment and insulation of the juncture between conductor 18a and the lead 20, and a substantial reinforcement or mechanical strengthening of the assemblage by reason of substantial envelopment of both the insulated conductor 18 and the appliance 21 by a continuous body of solidified resin 22a.

The present invention is not restricted to any particular thermosetting resin composition for use in the device. Many of the epoxy resin compositions well known to the art in the potting of the electrical components can be employed. Particularly good results can be obtained using epoxy resin systems in which resin and hardener components are supplied separately and mixed just prior to use to provide the thermosetting resin composition. Epoxy resin systems employing amine type hardener which will gel or solidify in less than two hours and reach a complete cure in less than about 48 hours at room temperature (25 C.) are well known in the art, and selection of a particular resin composition will depend upon the combination of mechanical and electrical (insulat-' ing) properties desired for the particular type of conductor-appliance juncture. In this connection, it is preferable to employ a resin composition which, as cured, has substantial flexibility combined with a tensile strength in excess of about 1000 psi. Such flexibility of the cured resin as it surrounds the insulated conductor in the tapered extension(s) supplements the inherent flexibility of the walls of the pod 10 in providing a graduated support to control and resist lateral movement of the protruding conductor(s) 18 with respect to the assemblage.

Thermosetting resin compositions which will gel in periods of less than two hours at room temperature must necessarily be utilized within a very limited time after mixing of the components. It is advantageous, therefore, particularly when devices of the present invention are to be used in the field, to supply the resin composition in two-compartment mixing containers, as for example, collapsible tubes with rupturable diaphragm means separating the compenents until mixing is desired, having a size and capacity to correspond with the volume of the particular pod or casing 10 with which it is to be used. Multi-compartment collapsible tubes of this type are well known in the art, and the feed tip 23, as shown in FIG. 6, can be visualized as the discharge tip of such a tube.

Various changes and modifications in the insulating and reinforcing means for conductor-appliance junctures as herein described will occur to those skilled in the art and to the extent that such changes and modifications are embraced by the appended claims, it is to be understood that they constitue part of the present invention.

I claim:

1. Insulating and strengthening means for applianceinsulated conductor junctures comprising a casing of thinwalled flexible plastic material, said casing having an essentially tubular body portion, conductor receiving means of elongated conically tapered contour protruding axially from one end of said tubular body adapted by cutting at an appropriate position longitudinally thereof, to closely envelop the insulated conductor to be associated therewith, the other end of said tubular body having a gradually inturned shoulder terminating in an axial aperture for circumferentially engaging a portion of the appliance to be associated therewith, the periphery of said aperture being a smoothly rounded continuation of the inner surface of said casing which meets the outer surface at a sharp angle, thereby providing for adaptation in aperture size to variations in appliance dimensions, said casing as mounted on an appliance-insulated conductor assemblage, providing therewith a chamber for receiving liquid resin composition with a portion thereof extending along and circumferentially engaging a portion of said appliance, a radial aperture centrally of said tubular body for introducing liquid resin composition to said chamber, and means for sealing said radial aperture to confine said liquid resin composition during solidification thereof.

2. Insulating and strengthening means for applianceinsula'ted conductor junctures as defined in claim 1 wherein portions of said tubular body at opposed sides of said radial aperture are outwardly deformed to provide a flattened area circumferentially of said aperture which is tangential to the outer surface of said tubular body, and the means for sealing said radial aperture is a fiat, circular closure plug having a peripheral groove providing snap engagement with said aperture.

(References on following page) 6 FOREIGN PATENTS References Cited UNITED STATES PATENTS 11/ 1958 Bollmeier 17493 4/ 1963 Bollmeier et a1.

LARAMIE E. ASKIN, Primary Examiner. 

1. INSULATING AND STRENGTHENING MEANS FOR APPLIANCEINSULATED CONDUCTOR JUNCTURES COMPRISING A CASING OF THINWALLED FLEXIBLE PLASTIC MATERIAL, SAID CASING HAVING AN ESSENTIALLY TUBULAR BODY PORTION, CONDUCTOR RECEIVING MEANS OF ELONGATED CONICALLY TAPERED CONTOUR PROTRUDING AXIALLY FROM ONE END OF SAID TUBULAR BODY ADAPTED BY CUTTING AT AN APPROPRIATE POSITION LONGITUDINALLY THEREOF, TO CLOSELY ENVELOP THE INSULATED CONDUCTOR TO BE ASSOCIATED THEREWITH, THE OTHER END OF SAID TUBULAR BODY HAVING A GRADUALLY INTURNED SHOULDER TERMINATING IN AN AXIAL APERTURE FOR CIRCUMFERENTIALLY ENGAGING A PORTION OF THE APPLIANCE TO BE ASSOCIATED THEREWITH, THE PERIPHERY OF SAID APERTURE BEING A SMOOTHLY ROUNDED CONTINUATION OF THE INNER SURFACE OF SAID CASING WHICH MEETS THE OUTER SURFACE AT A SHARP ANGLE; THEREBY PROVIDING FOR ADAPTATION IN APERTURE SIZE TO VARIATIONS IN APPLIANCE DIMENSIONS, SAID CASING AS MOUNTED ON AN APPLIANCE-INSULATED CONDUCTOR ASSEMBLAGE, PROVIDING THEREWITH A CHAMBER FOR RECEIVING LIQUID RESIN COMPOSITION WITH A PORTION THEREOF EXTENDING ALONG AND CIRCUMFERENTIALLY ENGAGING A PORTION OF SAID APPLIANCE, A RADIAL APERTURE CENTRALLY OF SAID TUBULAR BODY FOR INTRODUCING LIQUID RESIN COMPOSITION TO SAID CHAMBER, AND MEANS FOR SEALING SAID RADIAL APERTURE TO CONFINE SAID LIQUID RESIN COMPOSITION DURING SOLIDIFICATION THEREOF. 